Обсуждение: how to tell master from replica
Assuming a master & replica set up using streaming replication, hot standby, 9.3. I'd like to have a single script on both machines distinguish whether it's running on the machine with the master or replica,and take different actions accordingly. Is the way to do this to check for the presence of wal sender process vs wal receiver process? Or is there a query that couldexecuted against sys tables to find current running config of the local postmaster? -- Scott Ribe scott_ribe@elevated-dev.com http://www.elevated-dev.com/ (303) 722-0567 voice
On Wed, Sep 25, 2013 at 4:53 PM, Scott Ribe <scott_ribe@elevated-dev.com> wrote:
Assuming a master & replica set up using streaming replication, hot standby, 9.3.
I'd like to have a single script on both machines distinguish whether it's running on the machine with the master or replica, and take different actions accordingly.
Is the way to do this to check for the presence of wal sender process vs wal receiver process? Or is there a query that could executed against sys tables to find current running config of the local postmaster?
Would pg_is_in_backup() do the job?
http://www.postgresql.org/docs/9.3/static/functions-admin.html#FUNCTIONS-ADMIN-BACKUP
http://www.postgresql.org/docs/9.3/static/functions-admin.html#FUNCTIONS-ADMIN-BACKUP
On Thu, Sep 26, 2013 at 8:53 AM, Scott Ribe <scott_ribe@elevated-dev.com> wrote: > Assuming a master & replica set up using streaming replication, hot standby, 9.3. > > I'd like to have a single script on both machines distinguish whether it's running on the machine with the master or replica,and take different actions accordingly. > > Is the way to do this to check for the presence of wal sender process vs wal receiver process? Or is there a query thatcould executed against sys tables to find current running config of the local postmaster? "SELECT pg_is_in_recovery();" can be used to make the difference between a master and a slave. -- Michael
On Wed, Sep 25, 2013 at 5:11 PM, bricklen <bricklen@gmail.com> wrote:
On Wed, Sep 25, 2013 at 4:53 PM, Scott Ribe <scott_ribe@elevated-dev.com> wrote:Assuming a master & replica set up using streaming replication, hot standby, 9.3.
I'd like to have a single script on both machines distinguish whether it's running on the machine with the master or replica, and take different actions accordingly.
Is the way to do this to check for the presence of wal sender process vs wal receiver process? Or is there a query that could executed against sys tables to find current running config of the local postmaster?Would pg_is_in_backup() do the job?
http://www.postgresql.org/docs/9.3/static/functions-admin.html#FUNCTIONS-ADMIN-BACKUP
Sorry, meant "pg_is_in_recovery()". (Michael's response tipped me off)
On Sep 25, 2013, at 6:13 PM, Michael Paquier <michael.paquier@gmail.com> wrote: > "SELECT pg_is_in_recovery();" can be used to make the difference > between a master and a slave. Exactly what I need; thanks. -- Scott Ribe scott_ribe@elevated-dev.com http://www.elevated-dev.com/ (303) 722-0567 voice